Levonantradol is more than 300 times more potent than delta9-THC as an analgesic, but only 4.5 times more potent than delta9-THC as a cataleptogenic agent. Levonantradol (0.3-3.0 mg/kg, s.c.) decreased the turnover rate of acetylcholine in the hippocampus and striatum. In contrast, the turnover rate of acetylcholine in the parietal cortex was not affected by any dose of levonantradol. This pattern of activity is qualitatively similar to that of psychoactive cannabinoids, but differs from that of narcotic analgesics. Moreover, naltrexone administration did not antagonize the effects of levonantradol on striatal and hippocampal acetylcholine turnover rate. Thus, these results indicate that the pattern of activity on cholinergic dynamics elicited by levonantradol is consistent with a cannabinoid-like rather than an opiod-like mode of action.